>> I'm interested - please post links to photos when you have them. I'm>> always looking for better methods...> > Sure.>>> Tracker is a bit more tricky. I have the circuit design and>>> microcontroller programming, and will be glad to publish them, but are>>> you ready to solder circuit boards and burn microcontrollers?>> Probably (I've been working on computer circuitry since the early>> 1960's) - although my eyes aren't as good as they once were. I think I'd>> much prefer a passive pneumatic/hydraulic system to an>> electrically-driven system, though.> > To me it is not obvious how you can reach the cost, precision and> versatility of electronics.

Nor to me - that's why I was so interested in how you were solving that
problem. I really was looking for a solution - not a disagreement...

> A microcontroller is just a few dozens of cents wholesale price.> Adding a motor, you get it. And you get things that passive method> doesn't offer, such as emergency resting when the HTF circulation has> a trouble.

Very true. My primary application is for regions where there may be no
electrical infrastructure at all, and requiring any kind of
electricity-generating subsystem is not an option.

>> I'm not interested in water heating at all. I just want to heat air ->> and the 725F/325C is about all I need from the trough shown.> > No, it is not that you can get 325C at dry burning that you can get> 325C real heat output. The efficiency will drop to near zero at this> level. I've also got 300C+ temp for my earlier trough at dry burning,> even damaging the equipement. But with circulation, the only> reasonable thing is to heat water.

:) But I don't _need_ hot water (or even steam). We are addressing very
different requirements. BTW, 325C is a measure of temperature, not of
heat - although it works to think of temperature as a measure of heat
(energy) /density/.

> :) But I don't _need_ hot water (or even steam). We are addressing very > different requirements.

My apologies - it didn't occur to me until after I hit <send> that you
might find more information about the specific application helpful in
understanding what I'm doing.

The second drawing at

http://www.iedu.com/DeSoto/Projects/Stirling/Fluidyne.html

Is of a fluidyne (Stirling cycle heat engine) under development. The
heat produced is used to expand the air within the engine and is then
discarded to cause the air within the engine to contract.

This expansion/contraction provides a direct conversion from solar
energy to mechanical energy that can be used for a number of
applications (such as pumping and refrigeration) in regions where there
is neither fuel nor electricity available.

> The second drawing at> http://www.iedu.com/DeSoto/Projects/Stirling/Fluidyne.html > Is of a fluidyne (Stirling cycle heat engine) under development. The> heat produced is used to expand the air within the engine and is then> discarded to cause the air within the engine to contract.

Yes, I am greatly interested in that. Do you have a working model?
What is the cost and efficiency projection?

Posted by Morris Dovey on November 14, 2008, 4:46 pm

azuredu wrote:

> >> The second drawing at>>>> http://www.iedu.com/DeSoto/Projects/Stirling/Fluidyne.html >>>> Is of a fluidyne (Stirling cycle heat engine) under development. The>> heat produced is used to expand the air within the engine and is then>> discarded to cause the air within the engine to contract.> > Yes, I am greatly interested in that. Do you have a working model?> What is the cost and efficiency projection?

We have a working model only of the low-temperature version shown at the
bottom of

http://www.iedu.com/DeSoto/Projects/Stirling/Dyne.html

The fins have been removed from the cold end of the regenerator tube and
both the hot head and the regenerator are now wrapped with fiberglass
wool - and the materials cost of that engine is just under $00. We
don't have the means to acquire the data needed to calculate efficiency,
but have set a target of 25% or greater.

Since I last updated the web site I've started design and software
modeling activity for a version of the high-temperature engine that uses
air only (no fluid) which I've labeled a "dryadyne". I'm hoping that by
eliminating the fluid component altogether, efficiency will be
significantly improved and maintenance eliminated completely.

> > Yes, I am greatly interested in that. Do you have a working model?> > What is the cost and efficiency projection?> We have a working model only of the low-temperature version shown at the> bottom of> http://www.iedu.com/DeSoto/Projects/Stirling/Dyne.html

I should be missing something, but how do you do to output the
mechanical work?